The present invention is directed to a method of making a hollow article having an integral projection extending from a wall thereof, such as, a bottle with an integral handle thereon, in which both the hollow article and integral projection are fabricated of polyethylene terephthalate (PET).
There is a continuous demand for PET articles such as bottles, buckets, pitchers, cylinders, funnels, etc., because they are relatively inexpensive, easy to use and generally non-breakable. It is oftentimes desirable that articles of large size have handles thereon to aid in their use. U.S. Pat. No. 4,713,207 discloses a method of making a plastic container with an integral handle member thereon. The method disclosed includes the step of extruding a thermoplastic parison between sections of a mold and then blowing the container. Since it is generally understood that PET does not have sufficient hot melt strength to be extrusion blow molded, however, other thermoplastic materials, such as high density polyethylene and polyvinyl chloride, must be used to produce blow molded containers where the handle is integral with the container.
When PET is used and handles are desired, it has been the practice to attach the handle to the PET article in a separate operation, such as by ultrasonic fusion, after the blow molded PET article has been formed in and removed from the blow mold. Another approach has been to injection mold a thermoplastic handle in an operation separate and apart from the blow molding of the container, and snap the separately molded handle over the neck or finish of the blown PET bottle. In accordance with a still further proposal, the separately molded handle is inserted in the blow mold and the bottle is blown over/into the handle. None of these practices, however, has been entirely satisfactory since they add steps to the fabrication process, may require ultrasonic bonding equipment, and are otherwise unduly time-consuming and expensive.